Fuel spray system for internal combustion engines

ABSTRACT

A fuel spray system for a piston and cylinder-type internal combustion engine, particularly an aircraft engine provided with a throttled inlet manifold, a pump for supplying liquid fuel to a plurality of nozzles in the manifold, a device including means responsive to manifold pressure and means responsive to manifold temperature for controlling a fuel metering unit whereby the fuel flow to the nozzles is controlled.

United States Patent Clark is] 3,680,536 [4 1 Aug. 1, 1972 [54] FUEL SPRAY SYSTEM FOR INTERNAL COMBUSTION ENGINES [72] Inventor: Roger Cla rk, Dunelm, Dene Rd.,

Ashted, England [22] Filed: Aug. 6, 1970 [21] Appl. No.: 61,777

Related U.S. Application Data [63] Continuation-impart of Ser. No. 843,895, June 26, 1969, abandoned.

I52] U.S. Cl ..l23/l39 116, 123/139 AM, 123/140 MC [51 I Int. Cl ..FOZm 31/00 [58] Field oiSearch ..l23/ll9, 139.11 AL, 139.11 B-l39 .11AM,l23/l39.17 AV, 140 MC, 140 MD [56] 1 References Cited UNITED STATES PATENTS 3,320,938 5/1967 Homfeld et al. 123/139 2,670,724 3/1954 Reggio 4123/ 140 MC Primary Examiner-Laurence M. Goodridge Attorney-Holman & Stern [57] ABSTRACT A fuel spray system for a piston and cylinder-type internal combustion engine, particularly an aircraft engine provided with a throttled inlet manifold, a pump for supplying liquid fuel to a plurality of nozzles in the manifold, a device including means responsive to manifold pressure and means responsive to manifold temperature for controlling a fuel metering unit whereby the fuel flow to the nozzles is controlled.

4 Clains, 2 Drawing Figures PATENTED 3.680 536 sum 1 [IF 2 O INV NTOR W M BY ATTORNEYS FUEL SPRAY SYSTEM FOR INTERNAL COMBUSTION ENGINES This application is a continuation-in-part of my copending application Ser. No. 843,895 filed June 26, 1969, now abandoned, which in turn is a division of Ser. No. 696,603, now US. Pat. No. 3,487,820 dated Jan. 6, 1970.

BACKGROUND OF THE INVENTION This invention relates to fuel supply systems for piston and cylinder-type internal combustion engines of the kind in which a liquid fuel is injected through one or more nozzles, either into a manifold, through which a stream of air for combustion flows, or immediately before entry of the air into the cylinder of the engine.

For such a fuel supply system to be satisfactory, for use on an aircraft engine, it is desirable that such system should be sensitive to changes in various parameters relating to operating conditions. I

SUMMARY OF THE INVENTION The object of the invention is to provide a fuel supply system for a piston and cylinder-type internal combustion engine having an induction manifold for entry of air to'the combustion engine, a manually controllable throttle in the manifold for controlling the supply of air, a plurality of fuel injection nozzles arranged to supply liquid fuel to the manifold, a pump for providing a supply of liquid fuel to the nozzles, a fuel metering and distributing apparatus for controlling the supply of fuel to the nozzles, passage means connecting the pump, the metering and distributing apparatus and the nozzles, a spill passage connected between the pump and the metering and distributing apparatus, a device located in the spill passage, said device comprising a cam, the position of which cam controls the metering and distributing apparatus for varying the quantity of fuel delivered thereby, a piston and cylinder servo device connected to the cam for controlling its position, the servo device being in communication with the spill passage, a valve closure member, pressure responsive means connected to the valve closure member, the pressure responsive means being responsive to the pressure of air in the manifold, the valve closure member controlling the spill of fuel through the spill passage and also controlling the pressure fuel acting on the servo device, a temperature responsive element responsive to the temperature of the air in the manifold, and a linkage connecting the cam with the valve closure member of the pressure responsive means, the element and the servo device for providing respective forces to control the position of the cam.

Further objects and advantages of the invention will become more readily apparent to persons skilled in art from the following detailed description and annexed drawings.

BRIEF DESCRIPTIONS OF THE FIGURES FIG. 1 is a diagrammatic view of one form of system embodying the present invention, and

FIG. 2 is an enlarged view in perspective of a dividing mechanism constituting part of the fuel supply system.

DETAILED DESCRIPTION OF THE INVENTION The system is for use in supplying liquid fuel into a stream of pressurized air for combustion entering the engine and is particularly efiicacious for use in aircraft engines.

As illustrated in FIG. 1, an engine intake manifold 60 is provided with a turbo-super-charger 61 and a manual throttle 62. The turbo super-charger 61 is driven through a shaft 63, from a source of power (not illustrated) and is arranged in addition to supply a quantity of combustion air to the engine, to supply through a branch passage 64 a quantity of pressurized air for cabin pressurization in the aircraft.

It is thus necessary to supply liquid fuel to the manifold 60 at a position downstream of the branch passage 64 and in the illustrated embodiment, the fuel is delivered through a plurality of nozzles, one of which is indicated generally at65, at a position immediately before entry of the air to the engine cylinders. The nozzles 65 are arranged to inject metered quantities of fuel at regular intervals coinciding with the opening of the respective inlet valves operably related with the cylinders of the engine.

There is incorporated in the system a fuel quantity metering device denoted generally 66. The device 66 includes a body 67 in which is slidably mounted a shuttle 68. A pair of movable stops 69 and 70 are employed for limiting the stroke of the shuttle 68 and passages are formed in the body 67 for the entry of fuel from a distributor 71 which is driven from the engine via a shaft 72 so that measured quantities of fuel are delivered at timed intervals to the nozzle 65 in a known manner.

Preferably, the distributor 71 is of the face type and the passages to the nozzles are denoted at 73.

There is also included an engine driven gear-type pump 74 which obtains a fuel supply from a reservoir 75 through a filter 76 and fuel from the pump is delivered to the distributor 71 by way of a passage 77. Arranged in parallelism with the engine driven pump 74 is an electrically driven pump 78 with which is also associated a spill passage 79 for excess fuel. The passage 79 incorporates a pressurizing valve 80 and by means of a passage 81 communicates with the upstream or inlet side of the pumps 74 and 78.

It will further be noted that there is provided a device denoted generally 82 which is arranged for controlling one of the movable stops, namely, the stop 69 for the shuttle 68 in accordance with the intake manifold pressure and temperature. More specifically, the device 82 includes a body 83 which is in communication with the interior of the inlet manifold 60 and a bi-metallic element 84 is arranged to partake of the temperature conditions existing within the manifold 60. The pressure in the inlet manifold is exerted upon an evacuated capsule 85 through a passage 86 in the body 83. The capsule 85 is connected to a valve closure member 87 which is carried by one of a pair of diaphragms 88, 89 connected in the'body 83. The valve closure member 87 controls the flow through the passage 93 which terminates at a position between the diaphragms 88, 89. In a cylinder 90, provided in the body 83 is located a piston 91 and the interior of the cylinder 90 is in communication with the passage 77. A restricted passage 92 affords communication between opposite sides of the piston 91 in the cylinder 90 and the side of the piston which receives flow through the passage 92 at the downstream side of the restriction communicates with the passage 93, the escape of fuel through which is controlled by the position of the valve closure member 87.

A passage 94 is provided for the escape of fuel from the interior of the space defined between the two diaphragms 88 and 89 to the upstream or inlet side of the pumps 74 and 78.

The bi-rnetallic element 84, the valve closure member 87 and the piston 91 are all connected to a mechanism illustrated in FIG. 2 carrying a cam 95 pivotally mounted on the body 83 against which acts a spring-loaded member 96 which in turn controls the position of the movable stop 69. The mechanism is connected with the bi-metallic element 84 via a flexible strip 97 and with the valve closure member 87 through a similar strip 98..The position of the bi-metallic element 84 and also the position of the valve closure member 87, which is itself positioned by manifold pressure, determine the angular position of a part 99 of the mechanism which is mounted ona spindle 99a and to which part the strips 97 and 98 are suitably connected. The spindle 99a of the part 99 is connected to a lever 100 pivotally coupled at 101 to a further plate-type lever 102 which is mounted on a spindle 108 carrying the cam 95. The lever 102 in turn is connected to the piston 91 through a link 103.

The dividing mechanism illustrated in FIG. 2 has tension forces applied thereto from the capsule 85, the element 84 and the servo piston 91 respectively. If the lever 100 tends to swing either way to cause lack of alignment between the spindle 108 and the spindle 99a on which the part 99 is mounted, the plate-type lever 102 will move to restore this condition, thus also moving the cam 95. Thus, the balancing of these forces determines the angular position of the cam 95 and hence, the fuel quantity delivered to the engine.

Any change in any of the forces provides a change in the balance resulting in a new position of the cam 95. This in turn varies the permitted stroke of the shuttle 68.

It will be observed that in this embodiment, the capsule 85 includes a second compartment 104 with which the exhaust system of the engine communicates through a passage 105, thereby providing an additional force exerted upon the valve member 87.

The other movable stop, namely, the stop 70 for the shuttle 68, can be controlled by a manually operable lever 106 which is connected in a suitable manner to a cam 107. In one position, this is arranged to provide additional quantities of fuel for starting purposes and in a further position, the cam 107 can move the stop 70 to prevent any movement of the shuttle so that no fuel is delivered to the engine.

Moreover, the system can be modified to provide additional variations of the fuel supply in accordance with other parameters as may be desired.

What is claimed is:

1. A fuel system for a piston and cylinder-type internal combustion engine including an induction manifold for entry of air for combustion to the engine, a manually controllable throttle in the manifold for controlling the supply of air,.a plurality of fuel injection nozzles arranged to supply liquid fuel to the manifold, a

pump f r providing a supp] of li uid fuel to the nozzles, a ue metering and rstribu ng apparatus controlling the supply of fuel to the nozzles, passage means connecting the pump, the metering and distributing apparatus and the nozzles, a spill passage connected between the pump and the metering and distributing apparatus, a device operably related to the spill passage, said device comprising a cam, the position of which controls the metering and distributing apparatus for varying the quantity of fuel delivered thereby, a piston and cylinder servo unit connected to the cam to control its position with respect to the metering and distributing apparatus said servo unit being in communication with the spill passage, a valve closure member for controlling the spill of fuel through the spill passage and also the pressure of fuel acting on the servo unit, pressure responsive means connected to the valve closure member, the pressure responsive means being responsive to the pressure of air in the manifold, a temperature responsive element responsive to the temperature of the air in the manifold, and a linkage connecting the cam with the valve closure member of the pressure responsive means, the temperature responsive element and the servo unit for providing respective forces to control the position of the cam, said metering and distributing apparatus including a body, a shuttle slidably mounted within the body, a pair of movable stops within the body for limiting the stroke of the shuttle, a

spring-loaded member controlling the position of one of the movable stops, said linkage including a part mounted for rotary movement, a strip connected to said part and to the temperature responsive element, a second strip connected to said part and to the valve closure member, a lever to which said part is connected, a further lever mounted on a spindle carrying the cam, and said further lever being connected to the piston of the servo unit.

2. The fuel system as claimed in claim 1, in which the manifold is provided with a turbo supercharger for pressurizing the air flowing to the engine through the manifold, and said nozzles being disposed in the manifold at a location downstream of said supercharger.

3. The fuel system as claimed in claim 1, in which said device also includes means responsive to the pressure of the fuel, with said means acting on said cam to provide a further force to control its position.

4. The fuel system as claimed in claim 1, in which the pump is engine driven and a further pump is arranged for supplying fuel to the nozzles when the associated engine is being started. 

1. A fuel system for a piston and cylinder-type internal combustion engine including an induction manifold for entry of air for combustion to the engine, a manually controllable throttle in the manifold for controlling the supply of air, a plurality of fuel injection nozzles arranged to supply liquid fuel to the manifold, a pump for providing a supply of liquid fuel to the nozzles, a fuel metering and distributing apparatus controlling the supply of fuel to the nozzles, passage means connecting the pump, the metering and distributing apparatus and the nozzles, a spill passage connected between the pump and the metering and distributing apparatus, a device operably related to the spill passage, said device comprising a cam, the position of which controls the metering and distributing apparatus for varying the quantity of fuel delivered thereby, a piston and cylinder servo unit connected to the cam to control its position with respect to the metering and distributing apparatus said servo unit being in communication with the spill passage, a valve closure member for controlling the spill of fuel through the spill passage and also the pressure of fuel acting on the servo unit, pressure responsive means connected to the valve closure member, the pressure responsive means being responsive to the pressure of air in the manifold, a temperature responsive element responsive to the temperature of the air in the manifold, and a linkage connecting the cam with the valve closure member of the pressure responsive means, the temperature responsive element and the servo unit for providing respective forces to control the position of the cam, said metering and distributing apparatus including a body, a shuttle slidably mounted within the body, a pair of movable stops within the body for limiting the stroke of the shuttle, a spriNg-loaded member controlling the position of one of the movable stops, said linkage including a part mounted for rotary movement, a strip connected to said part and to the temperature responsive element, a second strip connected to said part and to the valve closure member, a lever to which said part is connected, a further lever mounted on a spindle carrying the cam, and said further lever being connected to the piston of the servo unit.
 2. The fuel system as claimed in claim 1, in which the manifold is provided with a turbo supercharger for pressurizing the air flowing to the engine through the manifold, and said nozzles being disposed in the manifold at a location downstream of said supercharger.
 3. The fuel system as claimed in claim 1, in which said device also includes means responsive to the pressure of the fuel, with said means acting on said cam to provide a further force to control its position.
 4. The fuel system as claimed in claim 1, in which the pump is engine driven and a further pump is arranged for supplying fuel to the nozzles when the associated engine is being started. 